It is our intention in this study to isolate individual human, interspersed repeated DNA sequences by recombinant DNA techniques and determine the structure, organization, evolution and functions of these sequences. We will begin these studies by determining the DNA sequence of the cloned repeated DNA sequences. Cloned members of individual repeated DNA sequence families will be used as probes in DNA renaturation experiments to map the interspersion pattern of the families with single copy DNA sequences and with other repeated DNA families. They will also be used as probes of other primate and mammalian genomes to study the evolution of each of the families. We have already demonstrated that the major family of human interspersed repeated DNA sequences function as RNA polymerase III promoters in vitro and possibly as origins of DNA replication. We will carry out a detailed characterization of the sequences found to be responsible for the RNA polymerase III function and also explore the possible replication function using DNA mediated transfers into eukaryotic cells. We will also explore the in vivo role of this transcriptional activity and explore potential influences of the papovavirus transformation proteins on these sequences.